feat(#4): Create new empty Mod project

[ModerRAS]

Summary

• Create IModProjectService interface
• Implement ModProjectService with BUTR template support
• Generate SubModule.xml, .csproj, and ModuleData folder
• Validate mod names and generate mod IDs
• Add comprehensive unit tests

Changes

• BannerlordModEditor.Common/Services/ModProjectService.cs - Implementation
• BannerlordModEditor.Common.Tests/Services/ModProjectServiceTests.cs - Unit tests

Closes #4

[Copilot]

Pull request overview

Adds a new service to generate an “empty mod project” skeleton (SubModule.xml, .csproj, ModuleData, etc.) with basic validation and corresponding unit tests.

Changes:

• Introduces IModProjectService plus ModProjectService implementation to scaffold a mod project on disk.
• Adds name validation + mod id generation logic and writes template files/folders (including optional BUTR package references).
• Adds xUnit tests covering validation and key project creation paths.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 8 comments.

File	Description
BannerlordModEditor.Common/Services/ModProjectService.cs	Implements mod project scaffolding, validation, mod-id generation, and csproj templating.
BannerlordModEditor.Common.Tests/Services/ModProjectServiceTests.cs	Adds xUnit coverage for validation, project creation, and SubModule.xml generation.

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[Copilot]

The validation error message is inconsistent with the actual validation rules: ValidateModName currently allows -, but the message says “underscores” only (and it also doesn’t mention the length constraints). Update the message to reflect the real rules or adjust the validator to match the message.

Suggested change

	result.ErrorMessage = "Invalid mod name. Use only letters, numbers, and underscores.";
	result.ErrorMessage = "Invalid mod name. Use only letters, numbers, underscores, and hyphens, and ensure it meets the required length constraints.";

[Copilot]

The validation error message is inconsistent with the actual validation rules: ValidateModName currently allows -, but the message says “underscores” only (and it also doesn’t mention the length constraints). Update the message to reflect the real rules or adjust the validator to match the message.

Suggested change

	return modName.All(c => char.IsLetterOrDigit(c) || c == '_' || c == '-');
	return modName.All(c => char.IsLetterOrDigit(c) || c == '_');

[Copilot]

CreatedFiles is currently used to store both file paths and directory paths (e.g., ModuleData). This makes the API ambiguous for callers. Consider either (a) renaming to something like CreatedPaths, or (b) splitting into CreatedFiles and CreatedDirectories (or similar) so consumers can reliably interpret the result.

Suggested change

	public List<string> CreatedFiles { get; set; } = new();
	public List<string> CreatedPaths { get; set; } = new();
	[Obsolete("Use CreatedPaths instead. This property will be removed in a future version.")]
	public List<string> CreatedFiles
	{
	get => CreatedPaths;
	set => CreatedPaths = value ?? new();
	}

[Copilot]

CreatedFiles is currently used to store both file paths and directory paths (e.g., ModuleData). This makes the API ambiguous for callers. Consider either (a) renaming to something like CreatedPaths, or (b) splitting into CreatedFiles and CreatedDirectories (or similar) so consumers can reliably interpret the result.

Suggested change

result.CreatedFiles.Add(moduleDataPath);

[Copilot]

Pre-creating bin/ and obj/ in a project template is generally undesirable because these are build output directories and can confuse tooling/users (and may create noise in scaffolding results). Prefer not creating them at scaffold time; keep the .gitignore entries and let the build generate these folders.

Suggested change

	var binPath = Path.Combine(projectPath, "bin");
	Directory.CreateDirectory(binPath);
	var objPath = Path.Combine(projectPath, "obj");
	Directory.CreateDirectory(objPath);

[Copilot]

Wrapping the synchronous, IO-heavy scaffolding in Task.Run will consume a thread-pool thread for the entire duration and doesn’t provide true async IO. Prefer either (1) making the method synchronous-only, or (2) implementing a genuinely async version that uses async file APIs (e.g., WriteAllTextAsync / async stream usage) and avoids Task.Run.

Suggested change

	public async Task<ModProjectResult> CreateModProjectAsync(ModProjectOptions options)
	{
	return await Task.Run(() => CreateModProject(options));
	public Task<ModProjectResult> CreateModProjectAsync(ModProjectOptions options)
	{
	return Task.FromResult(CreateModProject(options));

[Copilot]

There’s a new behavioral branch controlled by UseButrTemplate that changes the generated .csproj content, but the tests don’t currently assert that these conditional package references are present/absent. Add a test that creates a project with UseButrTemplate = false and verifies the generated .csproj does not contain the BUTR references (and optionally one that asserts they are present when true).

[Copilot]

The test hard-codes "/tmp" as the output directory, which will fail on Windows environments. Use Path.GetTempPath() (optionally combined with a GUID subfolder) to keep the test cross-platform and consistent with the other tests in this file.

Suggested change

	OutputDirectory = "/tmp"
	OutputDirectory = Path.Combine(Path.GetTempPath(), Guid.NewGuid().ToString())